Determine the vertex and axis of symmetry of y=−x2+8x+7

(1 point)
The vertex is:
.

The axis of symmetry is:
.

1 answer

Completing the square, we can rewrite the equation as:

y = -(x^2 - 8x) + 7

To complete the square, we need to add and subtract (8/2)^2 = 16 to the equation:

y = -(x^2 - 8x + 16 - 16) + 7

Simplifying:

y = -(x - 4)^2 + 7 - 16

y = -(x - 4)^2 - 9

So the vertex is (4, -9) and the axis of symmetry is x = 4.